The fact that it has a longer barrel, dosent change the fact that its still a 223.
AND, having different opinions is still legal, even in todays society.
My opinion is use it as you would any other 223, by using what shoots best for whatever you plan for its use.
Personally, i use 4895 with 50/55 gr bullets in mine, and if i want to use 70 gr id be using a bigger case like the same gun in a 22 250.
But theres probably no reason that both might work pretty well in your gun.